Valve fob



UNITED STATES PATENT OFFICE.

CORNALL BRADLEY, OF MANCHESTER, VIRGINIA.

VALVE FOR STEAM-ENGINES.

Specification of Letters Patent No. 16,351, dated January 6, 1857.

To all 'whom 'it may concem:

Be it known that I, CORNALL BRADLEY, of the town of Manchester, county of, Chesterfield, and State of Virginia, have invented a new and useful Improvement in the Valves of Steam-Engines to Prevent the Pressure of the Steam Thereon, and that the following is a full and exact description of the construction and operation thereof, reference being had to the accompanying drawings, making a part of this specification.

F igure 1 is a perspective View of the valve as it appears when adjusted and in its place, the top or cover of the steam chest is removed; and a portion of one side is broken out to show the parts more clearly. F ig. 2 is a sectional view through the center of the valve rod, and shows the internal arrangements of the va-lves in the Chamber.

The same letters indicate the same parts in both figures.

A, A, is a portion of the steam cylinder.

B, is the steam chest.

O is the face of the valve seat.

D is a metallic Chamber or ring, which is accurately turned out, and firmly fastened to the valve rod H.

E1 is the bottom or steam valve to admit steam to the cylinder. The back of this valve is turned so as to fit into the Chamber D on the valve rod. E2 is another valve similar to E1 and also fitted into the chamber D, and intended to work against the steam chest cover. The valves E1 and E2 are made so that a part of said valves which fit int-o the Chamber D, is exposed to the pressure of the steam inward; this is shown at F; both valves are packed in the chamber so as to be steam tight.

J is a continuation of the valve rod through the back end of the steam chest. This rod is hollow so as to make a communication from the' center of the Chamber out to the air.

Both valves are made so that the part of the valve against which the steam can exert a pressure downward against the seat (shown at G, G,) shall be larger, or contain more inches exposed to pressure, than the Circular part of' the same valve against which the steam can press inward into the Chamber or ring D. There is an opening in the steam chest cover, over the top valve,

l so that the steam can press the Valve up against the cover.

Such is the construction of my improvement.

The operation is as follows: Steam being admitted into the steam chest it will press down the valve on its seat, but, as there is no part of the valve exposed to the action of the steam downward except the part overlapping the ring or Chamber (G, G,) there can only be as much pressure downward as the number of inches so eXposed, at the same'time the steam is pressing on the Circular part of the same valve inward into the ring or chamber,-it follows that the real pressure on the face of the steam valve is as the number of inches exposed to downward pressure (G), less the number eXposed to a Contrary pressure into the Chamber at F.

The part of the valve at G must always be the largest to insure the retention of the valve to its seat, and to guard against the back pressure of the eXhaust.

The top valve D2 is made likev the bottom one, and its action is precisely similar.

The communication from the center of the Chamber with the air may be made through the top valve, in place of through the back end of valve rod J.

I do not wish to confine myself to a Circular Chamber on the valve rod for the back of the valves to fit into, as it is obvious that any other form would work equally as well.

I am aware that valves have been made heretofore to work against the steam chest Cover. This I make no claim to.

VVhat I claim as new and desire to secure by Letters Patent s The making the valves of steam'engines with two surfaces, one being exposed to the action of the steam downward against the valve seat, the other surface eXerting a contrary pressure into the Chamber, the inside of said Chamber being in communication with the atmosphere, the whole being ar- -ranged substantially as specie'd for the purpose set forth.

H CORNALL BRADLEY.

Witnesses:

Jnssn WHITEHEAD, WM. BRADLEY. 

